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Functional asymmetry in the descending cardiovascular pathways from dorsomedial hypothalamic nucleus.
- Source :
-
Neuroscience [Neuroscience] 2009 Dec 15; Vol. 164 (3), pp. 1360-8. Date of Electronic Publication: 2009 Sep 15. - Publication Year :
- 2009
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Abstract
- Neurons in the dorsomedial hypothalamus (DMH) play a key role in mediating tachycardia elicited by emotional stress. DMH activation by microinjections of the GABA(A) antagonist evokes tachycardia and physiological changes typically seen in experimental stress. DMH inhibition abolishes the tachycardia evoked by stress. Based on anatomic evidences for lateralization in the pathways from DMH, we investigated a possible inter-hemispheric difference in DMH-evoked cardiovascular responses. In anesthetized rats we compared changes in heart rate (HR), renal sympathetic activity (RSNA), mesenteric blood flow (MBF) and tail vascular conductance produced by activation of right (R) and left (L) sides of the DMH. We also evaluated the tachycardia produced by air jet stress after inhibition of R or L DMH. There were always greater increases in RSNA when bicuculline was injected ipsilaterally to the side where these parameters were recorded (average DeltaRSNA: L=+50% and R=+26%; P<0.05). Compared to pre-injection values, right DMH activation caused pronounced decrease (0.87+/-0.1% vs. 0.4+/-0.11%/mm Hg; P<0.05), whereas bicuculline methiodide (BMI) into left DMH produced no significant changes (0.95+/-0.09% vs. 1.04+/-0.25%/mm Hg) in tail vascular conductance. R or L DMH disinhibition produced decreases in MBF, but no differences in the range of these changes were observed. Activation of the right DMH caused greater tachycardia compared to the left DMH activation (average DeltaHR: R=+92 bpm; L=+48 bpm; P<0.05). Tachycardia evoked by air jet stress was smallest after right DMH inhibition (average DeltaHR: R=+57 bpm and L=+134 bpm; P<0.05). These results indicate that the descending cardiovascular pathways from DMH are predominantly lateralized and the right DMH might exert a prominent control on heart rate changes during emotional stress.
- Subjects :
- Animals
Autonomic Pathways cytology
Autonomic Pathways drug effects
Bicuculline pharmacology
Dorsomedial Hypothalamic Nucleus cytology
Dorsomedial Hypothalamic Nucleus drug effects
Efferent Pathways cytology
Efferent Pathways drug effects
GABA Antagonists pharmacology
Heart Rate physiology
Male
Rats
Rats, Wistar
Regional Blood Flow physiology
Splanchnic Circulation physiology
Stress, Psychological physiopathology
Sympathetic Fibers, Postganglionic anatomy & histology
Sympathetic Fibers, Postganglionic physiology
Sympathetic Nervous System anatomy & histology
Sympathetic Nervous System physiology
Tachycardia physiopathology
Autonomic Pathways physiology
Cardiovascular Physiological Phenomena
Dorsomedial Hypothalamic Nucleus physiology
Efferent Pathways physiology
Functional Laterality physiology
Subjects
Details
- Language :
- English
- ISSN :
- 1873-7544
- Volume :
- 164
- Issue :
- 3
- Database :
- MEDLINE
- Journal :
- Neuroscience
- Publication Type :
- Academic Journal
- Accession number :
- 19761813
- Full Text :
- https://doi.org/10.1016/j.neuroscience.2009.09.018